This invention relates to a network system having a plurality of network elements and a monitoring device for monitoring the network elements.
In general, a network system comprises a plurality of network elements connected to one another and a monitoring device connected to each of the network elements. Each of the network elements comprises a plurality of network units which may carry out a network process in cooperation with one another. Inasmuch as various faults may occur in each of network units, each of the network elements comprises a fault detecting circuit for detecting the faults of each network unit to produce fault signals different from one another. Each of the fault signal is representative of a detail message of the fault.
More particularly, the fault detecting circuit may produce first through N-th fault signals when first through N-th faults occur in a specific one of network elements, respectively, where N represents a positive integer which is greater than one. The first through the N-th fault signals are supplied from the specific network element to the monitoring device. The monitoring device monitors the specific network element on the basis of the first through the N-th fault signals.
The first through the N-th fault signals are representative of first through N-th fault messages, respectively. For example, the first through the N-th fault messages are defined by "Operations Technology Generic Requirements (OTGR): Operations Application Messages-Network Maintenance: Network Element and Transport Surveillance Messages" which is issued on 4 Dec., 1990.
In addition, each of the network elements is monitored or supervised by the monitoring device as described above. For example, supervision of the network elements is disclosed in "Framework Generic Requirements for Element Management Layer (EML) Functionality and Architecture" which is issued on 1 Aug., 1992.
As described above, the specific network element produces the first through the N-th fault signals when the first through the N-th faults occur in the specific network element. Therefore, the number of the fault signals increases as the positive integer N becomes greater and greater. When a large amount of faults occur in the specific network element, it is difficult for the monitoring device to supervise the specific network element. Namely, the load of the monitoring device increases over the capacity of the monitoring device.